What happened
On 2 August 2013, a Cameron C90 hot air balloon, registered F-HDBC, was participating in the second day of the French hot air balloon championship near Brigné, France. During the morning session, the pilot observed deteriorating weather conditions, specifically the onset of mist, and decided to perform an off-field landing in a nearby field.
As the balloon approached the landing site, the crew successfully flew over a set of medium-voltage powerlines with a clearance of approximately ten meters. However, as the balloon descended to about three meters above the ground, the envelope became entangled in a second set of powerlines. This second line branched off from a pole used by the first line at an angle of approximately 30 degrees to the balloon's flight path.
To mitigate the situation, the pilot activated the rapid deflation system to initiate an emergency descent. The resulting landing was hard, though the basket remained upright. The impact caused significant damage to the powerline infrastructure, breaking one of the three cables and damaging the remaining two. The two occupants successfully evacuated the basket after the pilot shut off the fuel supply.
The investigation
The BEA investigation focused on why the second set of powerlines was not identified during the approach. Investigators examined the weather conditions, which included light mist and a visibility of approximately 5,000 meters, as well as the aeronautical charts used by the crew. The investigation also reviewed the configuration of the electrical infrastructure, noting that the powerlines consisted of medium-voltage cables supported by 12-meter poles.
Findings
- The crew failed to detect the second powerline because it was positioned at an angle that made it difficult to perceive during the landing approach.
- The absence of the powerline from the aeronautical charts and maps used by the pilot prevented the crew from identifying the obstacle in advance.
- The inherent difficulty of spotting all obstacles, such as power and telephone lines, when selecting an off-field landing area contributed to the collision.